A few years ago i bought this tent-like-material when i was making a new seat for my motorcycle. The other day i wanted to make a strong, waterproof, lightweight backpack that can be folded up and put in your pocket and figured that the material i had would be perfect. There's lots of instructions online on how to make the string backpacks. It seemed pretty simple. I tried to sew it by hand but it wasn't near strong enough. So i went to the Salvation Army and bought a sewing machine for $30. I plugged it in at the store, pushed the pedal and it seemed to work, the needle went up and down... When i got home i tried using it but it...